Movable body system, pattern formation apparatus, exposure apparatus and exposure method, and device manufacturing method

ABSTRACT

A laser beam emitted by an encoder main body enters a wafer table via a PBS from the outside, and reaches a grating at a point that is located right under exposure area, and is diffracted by the grating. Then, by receiving interference light of a first polarized component that has returned from the grating and a second polarized component reflected by the PBS, positional information of the wafer table is measured. Accordingly, because the first polarized component, which has passed through PBS passes through the wafer table until it is synthesized with the second polarized component again, does not proceed through the atmosphere outside, position measurement of the wafer table can be performed with high precision without the measurement beam being affected by the fluctuation of the atmosphere around the wafer table.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to movable body systems, pattern formationapparatus, exposure apparatus and exposure methods, and devicemanufacturing methods, and more particularly to a movable body systemequipped with a movable body which moves holding an object, a patternformation apparatus equipped with the movable body system, an exposureapparatus equipped with the movable body system and an exposure methodin which an energy beam is irradiated on an object so as to form apredetermined pattern on the object, and a device manufacturing methodusing the exposure method.

2. Description of the Background Art

Conventionally, in a lithography process for manufacturing microdevices(electron devices and the like) such as semiconductor devices and liquidcrystal display devices, exposure apparatuses such as a reductionprojection exposure apparatus by a step-and-repeat method (a so-calledstepper) and a reduction projection exposure apparatus by astep-and-scan method (a so-called scanning stepper (which is also calleda scanner) are relatively frequently used.

In this kind of exposure apparatus, in order to transfer a pattern of areticle (or a mask) on a plurality of shot areas on an object subject toexposure such as a wafer or a glass plate (hereinafter, generallyreferred to as a wafer), a wafer stage holding the wafer is driven in anXY two-dimensional direction, for example, by linear motors and thelike. Position measurement of such a wafer stage was generally performedusing a laser interferometer whose stability of measurement values wasgood for over a long time and had a high resolution.

However, requirements for a stage position control with higher precisionare increasing due to finer patterns that accompany higher integrationof semiconductor devices, and now, short-term variation of measurementvalues due to temperature fluctuation of the atmosphere on the beam pathof the laser interferometer and/or the influence of temperature gradienthas come to occupy a large percentage in the overlay budget.

Meanwhile, as a measurement unit besides the laser interferometer usedfor position measurement of the stage, an encoder can be used, however,because the encoder uses a scale, which lacks in mechanical long-termstability (drift of grating pitch, fixed position drift, thermalexpansion and the like), it makes the encoder have a drawback of lackingmeasurement value linearity and being inferior in long-term stabilitywhen compared with the laser interferometer.

In view of the drawbacks of the laser interferometer and the encoderdescribed above, various proposals are being made (refer to U.S. Pat.No. 6,819,425 description, Kokai (Japanese Patent Unexamined ApplicationPublication) No. 2004-101362 bulletin and the like) of a unit thatmeasures the position of a stage using both a laser interferometer andan encoder (a position detection sensor which uses a diffractiongrating) together. Especially, encoders that have a measurementresolution nearly equal to or better than the laser interferometer haveappeared (for example, refer to U.S. Pat. No. 7,238,931 description andthe like) these days, and the technology to put the laser interferometerand the encoder described above together is beginning to gatherattention.

However, in the case a mirror of the interferometer or a scale (such asa grating) of the encoder is arranged on the outside, such as, forexample, on the side surface of a stage, a position (positional relationwith a predetermined point on the stage) on the stage changes along withthe minute deformation of the stage which occurs when the stage isaccelerated, which makes the probability high of a decrease in theposition measurement precision of the stage. Further, for example, fromthe viewpoint of improving throughput, even if a new technology wasproposed of beginning exposure during the acceleration of the waferstage in a scanning stepper, there is a risk that the change of theposition of the mirror or the scale on the stage that accompanies theacceleration of the stage described above will become an obstacle factorwhen practicing the new technology.

SUMMARY OF THE INVENTION

The present invention has been made in consideration of thecircumstances described above, and according to the first aspect of thepresent invention, there is provided a movable body system, the systemcomprising: a movable body that is movable substantially along apredetermined plane holding an object, and has a grating placed along aplane on a rear surface side of the object substantially parallel withthe predetermined plane, and light that has entered from the outside canproceed inside toward the grating; and a measurement system that makeslight enter the inside of the movable body from the outside, andmeasures positional information of the movable body in a measurementdirection in the predetermined plane by receiving light including areflected light from the grating.

According to this movable body system, the measurement system makeslight enter the inside of the movable body holding the object from theoutside, and positional information of the movable body in themeasurement direction in the predetermined plane is measured byreceiving the light including the reflected light from a gratingarranged on the rear surface of the object. Accordingly, positionmeasurement of the movable body with high precision becomes possiblewithout receiving almost any effect of fluctuation and the like of theatmosphere around the movable body.

According to a second aspect of the present invention, there is provideda pattern formation apparatus, comprising: a movable body system of thepresent invention, in which for pattern formation to an object, theobject is held by the movable body.

According to this apparatus, because the apparatus is equipped with themovable body and the movable body system which can perform positionmeasurement of object held by the movable body with high accuracy, itbecomes possible to perform formation of the pattern on the object withhigh precision.

According to a third aspect of the present invention, there is providedan exposure apparatus that forms a pattern on an object by anirradiation of an energy beam, the apparatus comprising: a patterningunit that irradiates the energy beam on the object; and a movable bodysystem according to the present invention, wherein a movable body thatholds the object of the movable body system is driven for relativemovement of the energy beam and the object.

According to this apparatus, because the apparatus is equipped with themovable body and the movable body system which can perform positionmeasurement of object held by the movable body with high accuracy, andthe movable body is driven using the movable body system so that theenergy beam and the object perform relative movement, it becomespossible to form a pattern on the object with high precision using thepatterning unit.

According to a fourth aspect of the present invention, there is provideda first exposure method in which an energy beam is irradiated on anobject so as to form a predetermined pattern on the object wherein amovable body that holds the object and also has a grating placed along asurface substantially parallel to a predetermined plane on a rearsurface side of the object, and in which light entering from the outsidecan proceed toward the grating in the inside, is moved along thepredetermined plane, and light is made to enter the inside of themovable body from the outside, and positional information of the movablebody in a measurement direction in the predetermined plane is measuredby receiving light including a reflected light from the grating.

According to this method, because in the movable body, positionalinformation of the movable body is measured by placing a grating on therear surface side of the object, making the light enter the inside ofthe movable body from the outside and receiving the light including thereflected light from a measurement point on the grating, positionmeasurement of the movable body with high precision without receivingalmost any effect of fluctuation and the like of the atmosphere aroundthe movable body, which leads to exposure (pattern formation) with highprecision, becomes possible.

According to a fifth aspect of the present invention, there is provideda second exposure method in which an energy beam is irradiated on anobject so as to form a predetermined pattern on the object wherein afirst and second lights are made to enter the inside of a movable bodythat holds the object and can move in a predetermined plane, and has agrating placed along a surface substantially parallel to thepredetermined plane on the rear surface side of the object, andpositional information of the movable body in the measurement directionin the predetermined plane is measured using a first and secondmeasurement unit which receive the light proceeding in the inside and isreflected by the grating, and a measurement of the positionalinformation of the movable body using one of the first and secondmeasurement units is switched to a measurement of the positionalinformation of the movable body using the other measurement unit of thefirst and second measurement units.

According to this method, because switching is performed from ameasurement of the positional information of the movable body using oneof the measurement units of the first and second measurement units to ameasurement of the positional information of the movable body using theother measurement unit, position control of the movable body can beperformed without any problems in particular even if the size of themovable body is reduced.

According to a sixth aspect of the present invention, there is provideda device manufacturing method, the method comprising: exposing asubstrate using an exposure method according to one of the first andsecond exposure methods of the present invention; and developing asubstrate which has been exposed.

According to a seventh aspect of the present invention, there isprovided a device manufacturing method, the method comprising: exposinga substrate using an exposure apparatus according to the presentinvention; and developing a substrate which has been exposed.

BRIEF DESCRIPTION OF THE DRAWINGS

In the accompanying drawings;

FIG. 1 is a schematic view that shows an exposure apparatus related to afirst embodiment;

FIG. 2 is a perspective view showing a positional relation between awafer table and an encoder main body in FIG. 1;

FIGS. 3A to 3C are views for describing a measurement by the encodermain body in the first embodiment;

FIGS. 4A to 4C are views to describing a modified example of a wafertable and an encoder related to the first embodiment;

FIGS. 5A to 5C are views for describing a measurement by an encoder mainbody in a second embodiment;

FIGS. 6A to 6C are views for describing a measurement by an encoder mainbody in a third embodiment;

FIG. 7 is a planar view that shows an exposure apparatus partiallyomitted related to a fourth embodiment;

FIG. 8 is a front view that shows a part of an exposure apparatusrelated to a fifth embodiment;

FIG. 9 is a view that shows a configuration of a wafer stage and anencoder main body which performs position measurement of the wafer stagein FIG. 8;

FIG. 10 is a flow chart for explaining an embodiment of the devicemanufacturing method; and

FIG. 11 is a flow chart that shows a concrete example of step 404 inFIG. 10.

DESCRIPTION OF THE EMBODIMENTS A First Embodiment

An embodiment of the present invention will be described below, withreference to FIGS. 1 to 3C.

FIG. 1 shows a schematic configuration of an exposure apparatus 100related to the first embodiment of the present invention. Exposureapparatus 100 is a reduction projection exposure apparatus by astep-and-scan method. Exposure apparatus 100 is equipped with anillumination system 12 including a light source and an illuminationoptical system and illuminates a reticle R by an illumination light IL,a reticle stage RST that holds reticle R, a projection optical systemPL, a wafer stage WST that holds wafer W, a controller (not shown) whichhas overall control over the system and the like. In the descriptionbelow, a direction parallel to an optical axis AX of projection opticalsystem PL will be described as the Z-axis direction, a direction withina plane orthogonal to the Z-axis direction in which a reticle and awafer are relatively scanned will be described as the Y-axis direction,a direction orthogonal to the Z-axis and the Y-axis will be described asthe X-axis direction, and rotational (inclination) directions around theX-axis, the Y-axis, and the Z-axis will be described as θx, θy, and θzdirections, respectively.

Illumination system 12 illuminates a slit-shaped illumination areaextending in the X-axis direction on reticle R set by a reticle blind(not shown), with an approximately uniform illumination by illuminationlight IL. In this case, as illumination light IL, for example, an ArFexcimer laser beam (wavelength 193 nm) is used.

On reticle stage RST, reticle R on which a circuit pattern or the likeis drawn is fixed, for example, by vacuum suction or the like. Forposition control of reticle R, reticle stage RST is finely drivable inthe XY plane which is perpendicular to an optical axis (coinciding withoptical axis AX of projection optical system PL described below) ofillumination system 12 by a reticle stage drive system (not shown), andis drivable at a designated scanning speed in a predetermined scanningdirection (in this case, the Y-axis direction, which is the lateraldirection in the page surface of FIG. 1).

The position of reticle stage RST in the movement plane is constantlydetected by a reticle laser interferometer (hereinafter called a“reticle interferometer”) 324 via a side surface of reticle stage RST ata resolution of, for example, around 0.5 to 1 nm. The positionalinformation of reticle stage RST from reticle interferometer 324 is sentto the controller (not shown). The controller drives reticle stage RSTvia the reticle stage drive system, based on positional information ofreticle stage RST.

As projection optical system PL, for example, a dioptric system is used,consisting of a plurality of lenses (lens elements) that is disposedalong optical axis AX, which is parallel to the Z-axis direction.Projection optical system PL is, for example, both-side telecentric, andhas a predetermined projection magnification (such as one-quarter orone-fifth times). Therefore, when illumination light IL fromillumination system 12 illuminates the illumination area, a reducedimage of the circuit pattern (a reduced image of a part of the circuitpattern) of the reticle is formed within the illumination area withillumination light IL that has passed through reticle R which is placedso that its pattern surface substantially coincides with a first plane(an object plane) of projection optical system PL, in an area (exposurearea IA) conjugate to the illumination area on wafer W whose surface iscoated with a resist (a sensitive agent) and is placed on a second plane(an image plane side), via projection optical system PL. And by thesynchronous drive of reticle stage RST and wafer stage WST, reticle R isrelatively moved in the scanning direction (the Y-axis direction) withrespect to the illumination area (illumination light IL) while wafer Wis relatively moved in the scanning direction (the Y-axis direction)with respect to exposure area IA (illumination light IL), thus scanningexposure of a shot area (divided area) on wafer W is performed, and thepattern of the reticle is formed on the shot area. That is, in theembodiment, the pattern is generated on wafer W according toillumination system 12, reticle R, and projection optical system PL, andthen by the exposure of the sensitive layer (resist layer) on wafer Wwith illumination light IL, the pattern is formed on wafer W.

Wafer stage WST holds wafer holder WH by suction by an electrostaticchuck mechanism (not shown) on its upper surface. Further, wafer holderWH holds wafer W by suction by the electrostatic chuck mechanism thatwafer holder WH has. As shown in FIG. 1, wafer stage WST includes astage main section 14, a wafer table WTB fixed on stage main section 14,and a freely detachable wafer holder WH which can be attachedto/detached from wafer table WTB by the electrostatic chuck mechanism(not shown). Incidentally, the holding mechanism for fixing wafer holderWH to wafer table WTB is not limited to the electrostatic chuckmechanism, and for example, a vacuum chuck mechanism or a clampingmechanism can also be used. Further, wafer holder WH can be formedintegral with wafer table WTB, or wafer W can be held by a mechanismdifferent from the electrostatic chuck mechanism, such as a vacuum chuckmechanism.

Stage main section 14 (wafer stage WST) is driven in directions of sixdegrees of freedom, in the X-axis direction, the Y-axis direction, theZ-axis direction, the θx direction, the θy direction and the θzdirection by a drive system which includes a linear motor, a voice coilmotor (VCM) and the like. Accordingly, wafer W can be moved indirections of six degrees of freedom. Incidentally, stage main section14 can be driven in the X-axis direction, the Y-axis direction, and theθz direction, and wafer table WTB can be finely driven in the Z-axisdirection, the θx direction, and the θy direction. In this case, wafertable WTB can be finely moved in directions of six degrees of freedom.

Wafer table WTB consists of a transparent member (e.g., glass or thelike), and is a plate-shaped member having a rough square shape in aplanar view (when viewed from above). The length of one side of wafertable WTB is around 3 times the diameter of wafer W. Wafer holder WH isheld on the upper surface in the center section of wafer table WTB.Because a laser beam for measurement of an encoder system describedbelow travels inside wafer table WTB, wafer table WTB is configured by atransmission member transmissive to at least the laser beam formeasurement. Further, wafer table WTB has a first surface (uppersurface) and a second surface (lower surface) which are substantiallyparallel to the XY plane, a pair of sides each extending in the X-axisdirection, and a pair of sides each extending in the Y-axis direction.In the embodiment, as it will be described later on, a grating 24 isformed on the upper surface of wafer table WTB, and the laser beam formeasurement enters the inside of wafer table WTB from each of the foursides (hereinafter also referred to as the edge surface). Incidentally,the transmission member is preferably a material having low thermalexpansion, and as an example in the embodiment, synthetic silica isused. Further, wafer table WTB can be totally configured by thetransmission member, however, wafer table WTB can also be configuredwith only a part of wafer table WTB where the laser beam for measurementpasses configured by the transmission member.

As shown in FIG. 3A, the −Y side edge surface and the +Y side edgesurface of wafer table WTB extend in the X-axis direction, and areinclined at a predetermined angle (θ (0°<θ<90°)) with respect to the XZplane. More specifically, the −Y side edge surface and the +Y side edgesurface form an angle with the bottom surface of wafer table WTB (lowersurface) that is an acute angle (90°−θ), in other words, the angleformed with the upper surface (a formation surface of grating 24) ofwafer table WTB becomes an obtuse angle (90°+θ). Furthermore, to each ofthe −Y side edge surface and the +Y side edge surface, a polarizationfilter (hereinafter also simply referred to as a “PBS”) 18 is affixed.Further, although it is not shown, in a similar manner, the −X side edgesurface and the +X side edge surface of wafer table WTB extend in theY-axis direction, and are inclined at a predetermined angle (θ) withrespect to the YZ plane. More specifically, the −X side edge surface andthe +X side edge surface form an angle with the bottom surface of wafertable WTB (lower surface) that is an acute angle (90°−θ), in otherwords, the angle formed with the upper surface of wafer table WTBbecomes an obtuse angle (90°+θ). Furthermore, to each of a −X side edgeface and the +X side edge face, a polarization filter (PBS) (not shown)is affixed.

PBS18 is configured, for example, including a pair of glass plates and apolarizing film which is inserted between the pair of glass plates, andhas a property of transmitting a polarized component whose vibration isin a particular direction while reflecting other polarized components.In this case, of the lights entering PBS18, a first polarized componenthaving vibration in a particular direction is to pass, and a secondpolarized component having vibration in a direction orthogonal to thefirst polarized component is to be reflected.

Further, on the upper surface of wafer table WTB in the center section(a section which is one size larger than wafer holder WH), atwo-dimensional grating 24, which is a combination of a grating whoseperiodic direction is the X-axis direction and a grating whose periodicdirection is the Y-axis direction, is set horizontally, and the uppersurface of grating 24 is covered by a cover glass 51 serving as aprotective member. In the embodiment, the above-mentioned electrostaticchuck mechanism wafer holder WH is adsorbed, and to hold is installed inthe upper surface of this cover glass 51. Incidentally, in theembodiment, cover glass 51 is arranged to cover almost the entiresurface of the upper surface of wafer table WTB, however, cover glass 51can be arranged so that it covers only a part of the upper surfaceincluding grating 24. Further, in the embodiment, cover glass 51 isconfigured of a material the same as wafer table WTB, however, forexample, cover glass 51 can be configured of other materials such as,for example, metal, ceramics or a thin film. Incidentally, wafer tableWTB can include cover class 51, and in this case, the formation surfaceof grating 24 is to be placed inside wafer table WTB and not on the topsurface of wafer table WTB.

The position of wafer stage WST in the XY plane is constantly detectedvia grating 24 by a main body of an encoder which will be describedbelow. The positional information of wafer stage WST detected by themain body of this encoder is sent to the controller (not shown), andbased on this positional information, the controller (not shown)controls the position of wafer stage WST by driving the linear motor andvoice coil motor previously described.

The controller includes, for example, work stations (or microcomputers)and the like, and has overall control over each section that configuresexposure apparatus 100 such as the detection system described above.

Next, configuration and the like of the encoder system (measurementsystem) used for position measurement of wafer stage WST in the firstembodiment will be described in detail, using FIGS. 1 to 3C. The encodersystem of the first embodiment includes grating 24 previously described,and four encoder main bodies (measurement units) 16Ya, 16Yb, 16Xa, and16Xb (encoder main bodies 16Xa and 16Xb not shown in FIG. 1, refer toFIG. 2) which irradiate a laser beam for measurement on grating 24.

FIG. 2 shows a perspective view for explaining the positional relationbetween the four encoder main bodies 16Ya, 16Yb, 16Xa, and 16Xb. Encodermain bodies 16Ya and 16Yb are used to detect positional information ofwafer table WTB (wafer W) in the Y-axis direction. As shown in FIG. 2,encoder main bodies 16Ya and 16Yb are placed at positions spaced apartat an equal interval on the −Y side and the +Y side from the center (theexposure center) of exposure area IA. Further, encoder main bodies 16Xaand 16Xb are used to detect positional information of wafer table WTB(wafer W) in the X-axis direction. As shown in FIG. 2, encoder mainbodies 16Xa and 16Xb are placed at positions spaced apart at an equalinterval on the −X side and the +X side from the center of exposure areaIA. Incidentally, in the embodiment, the center of exposure area IAcoincides with optical axis AX of projection optical system PL in the XYplane, and in the exposure operation, positioning (more specifically,alignment of wafer W) of wafer stage WST is performed with respect tothe center of exposure area IA.

Now, encoder main body 16Ya will be specifically described. Although itis not shown, encoder main body 16Ya includes a photodetector, which isconfigured including a light source that emits a laser beam formeasurement (hereinafter appropriately shortened to a laser beam), anoptical system, a CCD and the like inside.

As shown in FIG. 3A, in encoder main body 16Ya, a laser beam Ly1 formeasurement is emitted from the light source arranged inside encodermain body 16Ya. And as shown in FIG. 3A, laser beam Ly1 perpendicularlyenters PBS18 arranged on the −Y edge surface of wafer table WTB. Then,by PBS18, laser beam Ly1 is split by polarization into a first polarizedcomponent and a second polarized component whose polarization directionsare orthogonal to each other. More specifically, one of the firstpolarized component and the second polarized component (in this case,the first polarized component) passes PBS18, and the other polarizedcomponent (in this case, the second polarized component) is reflected byPBS18.

Then, the first polarized component (e.g., a p-polarized component)which has passed PBS18 proceeds into the inside of wafer table WTB, andthen enters a bottom surface 22 a at an incidence angle (90°−θ) and isreflected here and then enters grating 24 at an incidence angle (90°−θ).Then, the component is diffracted with the grating of grating 24 whoseperiodic direction is the Y-axis direction, and diffraction light of apredetermined order returns the same optical path as the optical path ofthe laser beam that had entered grating 24. Now, as is obvious fromFIGS. 3A to 3C, in the embodiment, light incident on grating 24 isalways set to be incident on a point IAa right under the center of anexposure area IA. The position of this point IA in the XY plane is thesame as the center of exposure area IA.

Then, the return light (the return light of the light (the firstpolarized component) that has passed PBS18) passes the same optical pathas the second polarized component (e.g., an s-polarized component)reflected by PBS18, and returns to encoder main body 16Ya.

In encoder main body 16Ya, the reflected light of the first polarizedcomponent reflected by grating 24 and the reflected light of the secondpolarized component reflected by PBS18 is synthesized into aninterference light by the optical system (e.g., including the polarizerand the like), and the interference light is received by thephotodetector, which detects an interference fringe formed on aphotodetection surface of the photodetector. This detection result issent to the controller (not shown), and the controller computespositional information related to the Y-axis direction of wafer tableWTB (wafer W) from the detection result.

Referring back to FIG. 2, the configuration of encoder main body 16Yb isalso similar to encoder main body 16Ya. More specifically, although itis not shown, encoder main body 16Yb includes a photodetector, which isconfigured including a light source that emits a laser beam formeasurement, an optical system, a CCD and the like inside. Laser beamLy2 emitted from encoder main body 16Yb is also is split by polarizationinto a first polarized component (passing light) and a second polarizedcomponent (reflected light) by PBS18 arranged on the +Y edge surface ofwafer table WTB. Of the polarized component (the first polarizedcomponent) that has passed through PBS18, the light which returns viabottom surface 22 a and the grating of grating 24 whose periodicdirection is in the Y-axis direction and the light of the polarizedcomponent reflected by PBS18 (the second polarized component) return toencoder main body 16Yb. In this case, of laser beam Ly2 emitted fromencoder main body 16Yb, the light incident on grating 24 is alwaysincident on point IAa right under the center of exposure area IA onwhich laser beam Ly1 is incident. Then, an interference light isreceived with the photodetector in encoder main body 16Yb, and based onthe detection result, the controller (not shown) computes positionalinformation related to the Y-axis direction of wafer table WTB (waferW).

In the embodiment, as shown in FIGS. 3A to 3C, laser beam Ly1 emittedfrom encoder main body 16Ya and laser beam Ly2 emitted from encoder mainbody 16Yb respectively enter PBS18, and are incident on the same pointIAa right under the center of exposure area IA. Therefore, while wafertable WTB moves in the range shown in FIGS. 3A to 3C in the Y-axisdirection which is a measurement direction, the positional informationof wafer table WTB in the Y-axis direction can be constantly measuredusing encoder main bodies 16Ya and 16Yb. Further, while exposure area IAis located at least on wafer W, laser beams Ly1 and Ly2 do not move awayfrom PBS18 even if wafer stage WST moves in the X-axis direction.Therefore, positional information of wafer table WTB in the Y-axisdirection can be constantly measured by encoder main bodies 16Ya and16Yb, at least during the exposure operation.

Accordingly, the controller (not shown) averages measurement results(coordinate values) according to the encoder main bodies (16Ya, 16Yb)which can measure the positional information in the Y-axis direction,and computes the average value as positional information in the Y-axisdirection.

Incidentally, also for encoder main bodies 16Xa and 16Xb that performposition measurement related to the X-axis direction, only the pointswhere the measurement direction is in the X-axis direction and withthis, the outgoing direction of laser beams Lx1 and Lx2 for measurement(refer to FIG. 2) is parallel to the an XZ plane, and where the gratingof grating 24 whose periodic direction is in the X-axis direction aredifferent, and other configurations and measuring methods are similar.Further, while exposure area IA is located at least on wafer W, laserbeams Lx1 and Lx2 do not move away from PBS18 even if wafer stage WSTmoves in the Y-axis direction. Accordingly, at least during the exposureoperation, the positional information of wafer table WTB in the X-axisdirection can be constantly measured using encoder main bodies 16Xa and16Xb, respectively. The controller (not shown) averages measurementresults (coordinate values) according to the encoder main bodies 16Xaand 16Xb as in the description above, and computes the average value aspositional information of wafer table WTB in the X-axis direction.

As described above, according to the embodiment, laser beams Ly1, Ly2,Lx1, and Lx2 emitted from encoder main bodies 16Ya, 16Yb, 16Xa, and 16Xbenter wafer table WTB from the outside, and reach point IAa which islocated right under the center of exposure area IA and are diffractedwith grating 24. Then, by receiving the interference light of the firstpolarized component returning from grating 24 and the second polarizedcomponent reflected by PBS18 with the photodetector of each encoder mainbody, positional information of wafer table WTB is measured.Accordingly, until the first polarized component which has passedthrough PBS18 is synthesized with the second polarized component, ormore specifically, until the first polarized component is emittedoutside PBS18, the first polarized component passes inside wafer tableWTB and does not proceed in the atmosphere outside. Therefore, betweenPBS18 and grating 24, the first polarized component (measurement beam)is not affected by the fluctuation of the atmosphere around wafer tableWTB. Furthermore, outside wafer table WTB, the first polarized componentand the second polarized component pass the same optical path.Accordingly, it becomes possible to perform a highly precise positionmeasurement of wafer table WTB.

Further, in the embodiment, because position measurement of wafer tableWTB can be performed with high accuracy, it becomes possible for thecontroller to relatively move reticle R and wafer W with good precisionby moving wafer table WTB, based on the measurement result. Accordingly,exposure with high precision can be realized.

Further, in the embodiment, because grating 24 is arranged on the rearsurface of wafer holder WH of wafer table WTB, the position of grating24 on wafer table WTB does not minutely change due to acceleration ofwafer table WTB. Therefore, position measurement with high precision canbe performed even when wafer table WTB is being accelerated.Accordingly, it becomes possible to start exposure, for example, evenduring acceleration, and a high throughput can be expected.

Further, in the embodiment, because the position of wafer table WTB ismeasured at predetermined point IAa directly under the center ofexposure area IA, position measurement can be performed with highprecision without an Abbe error, and by performing position control ofthe wafer on exposure using the measurement result, it becomes possibleto perform exposure with high precision.

Incidentally, in the embodiment above, for the sake of convenience, apair of encoder main bodies (encoder main bodies for Y positionmeasurement) which measures positional information in the Y-axisdirection and a pair of encoder main bodies (encoder main bodies for Xposition measurement) which measures positional information in theX-axis direction were arranged, however, the present invention is notlimited to this, and for example, in the case of measuring yawing(rotation information in the θz direction) of wafer table WTB, at leastone of the encoder main body for Y position measurement and the encodermain body for X position measurement can be arranged in two or morepairs. In this case, the two pairs of encoder main bodies can be placedso that the laser beams for measurement are incident on the grating atpositions equally distant with the center of exposed areas IA inbetween. For example, in the case two pairs of encoder main bodies for Yposition measurement is arranged, the irradiation point of the laserbeam for measurement from a first pair of encoder main bodies and theirradiation point of the laser beam for measurement from a second pairof encoder main bodies are set at the same position as the center ofexposure area IA in the Y-axis direction and also at positions equallydistant from the center of exposure area IA in the X-axis direction. Inthis case, positional information in the θz direction can be obtainedfrom measurement values of at least one of the first pair of encodermain bodies and at least one of the second pair of encoder main bodies.Further, the first pair of encoder main bodies and one of the secondpair of encoder main bodies, or one each of the pairs of encoder mainbodies can be arranged, and positional information of wafer table WTB inthe Y-axis direction and the θz direction can be obtained from themeasurement values of these two or three encoder main bodies.

Incidentally, in the embodiment above, the case has been described wherethe Y position (the X position) of wafer table WTB was decided byaveraging the measurement values (coordinate values) of the encoder mainbodies for Y position measurement (or the encoder main bodies for Xposition measurement), however, the present invention is not limited tothis, and the Y position (or the X position) can be one of themeasurement values of a pair of encoder main bodies. In this case, forexample, one of the encoder main bodies can be constantly used and theother encoder main body can be used only when the one main body can nolonger perform measurement for some reason, or, for example, the pair ofencoder main bodies can be switched hourly. Further, for example, one ofthe encoder main bodies can be constantly used, and the other encodercan be used for calibration (adjustment) of the one encoder main body.

Further, in the embodiment above, a pair of encoder main bodies for Xposition measurement and a pair of encoder bodies for Y positionmeasurement whose irradiation point (that is, measurement point of theencoder main body) of the laser beams for measurement is at the sameposition were arranged, and the average value of the measurement results(coordinate values) of a pair of encoder main bodies whose measurementdirection is the same was decided as the positional information of wafertable WTB in the measurement direction. However, the present inventionis not limited to this, and the measurement point of a pair of encodermain bodies whose measurement direction is the same can be placed at adifferent position in a direction besides the measurement directionwhich is orthogonal to the measurement direction within the XY plane,such as for example, a position symmetric to the center of exposure areaIA. In other words, the measurement axes (coinciding with the laserbeams for measurement in the embodiment above) of the pair of encodermain bodies whose measurement direction is the same can be placedshifted in a direction orthogonal to the measurement axes in the XYplane. In this case, positional information of wafer table WTB in themeasurement direction can be obtained from at least one of themeasurement results (coordinate values) of the pair of encoder mainbodies, and positional information of wafer table WTB in the θzdirection can be obtained from both of the measurement results. In theembodiment above, the measurement axes (and an incidence direction ofthe laser beam for measurement) of the pair of encoder main bodies whosemeasurement direction is the same, are parallel with the measurementdirection. Incidentally, in the pair of encoder main bodies whosemeasurement direction is the same, the position of the measurement pointcan be made to differ in both the X-axis and the Y-axis directions.Further, in the embodiment above, the pair of encoder main bodies whosemeasurement direction is the same was placed on both sides with wafertable WTB in between, however, the encoder main bodies can be arrangedon the same side with respect to wafer table WTB. In this case, not onlypositional information in the measurement direction but also positionalinformation in the θz direction can be measured. Furthermore, in theembodiment above, a pair of encoder main bodies for X positionmeasurement and a pair of encoder main bodies for Y position measurementwere arranged, however, the number of encoder main bodies is not limitedto four, and can be three or less or five or more. For example, only oneof an encoder main body for X position measurement and an encoder mainbody for Y position measurement can be arranged, and the other can bearranged in pairs. In this case, by placing the pair of encoder mainbodies on the same side with respect to wafer table WTB, it becomespossible to measure positional information in the X-axis and Y-axisdirections and positional information in the θz direction. Or, only oneencoder main body for X position measurement and/or one encoder mainbody for Y position measurement can be arranged to measure positionalinformation of wafer table WTB in the X-axis and/or Y-axis direction.Even in this case, measurement by the encoder main body is constantlyperformed, which makes it possible to realize wafer positioning withhigh precision.

Incidentally, in the embodiment above, the case has been described wherethe −Y side edge surface and the +Y side edge surface of wafer table WTBwere inclined at a predetermined angle (θ) with respect to the XZ planeand the −X side edge surface and the +X side edge surface of wafer tableWTB were inclined at a predetermined angle (θ) with respect to the YZplane, however, the present invention is not limited to this. Forexample, as shown in FIG. 4A and the like, the −Y side edge surface andthe +Y side edge surface of wafer table WTB can be inclined at apredetermined angle (−θ) with respect to the XZ plane and the −X sideedge surface and the +X side edge surface of wafer table WTB can beinclined at a predetermined angle (−θ) with respect to the YZ plane. Inthis case, the Y side edge surface and the X side edge surface both forman obtuse angle (90+θ) with the bottom surface of wafer table WTB, ormore specifically, form an acute angle (90°−θ) with the upper surface(the grating surface on which grating 24 is formed). Further, as shownin FIG. 4A, laser beams Ly1 and Ly2 (and, Lx1 and Lx2) each are incidenton the corresponding edge surface perpendicularly. Incidentally, becausethe configuration of other sections is totally the same as theembodiment above, the description here will be omitted.

Even if such a configuration is employed, as in the embodiment above,laser beams Ly1 and Ly2 (and, Lx1 and Lx2) for measurement emitted fromencoder 16Ya and 16Yb (16Xa and 16Xb) are incident on point IAa rightunder the center of exposure area IA (refer to FIGS. 4A to 4C).Accordingly, in the case of employing the configuration shown in FIGS.4A to 4C, it is possible to perform position measurement of wafer tableWTB similarly as in the embodiment above. Further, in the case ofemploying the configuration shown in FIGS. 4A to 4C, because laser beamsLy1 and Ly2 (and, Lx1 and Lx2) for measurement do not have to bereflected by the bottom surface of wafer table WTB, it is possible toreduce the size of wafer table WTB in the Y-axis direction and theX-axis direction, as it can be seen when comparing FIG. 4A and the likeand 3A and the like. Further, in the configuration shown in FIGS. 4A to4C, it is possible to reduce the angle formed between the obliquelyincident laser beam for measurement and grating 24 without increasingthe size of wafer table WTB in the X-axis and the Y-axis directions.Because of this, compared to the embodiment above, the size (height orthickness) of wafer table WTB in the Z-axis direction can be reduced.Accordingly, in the configuration shown in FIGS. 4A to 4C, the size ofwafer table WTB can be greatly reduced when compared with the embodimentabove.

A Second Embodiment

Next, a second embodiment of the present invention will be described,referring to FIGS. 5A to 5C. As shown in FIGS. 5A to 5C, in the secondembodiment, the point where a wafer table WTB slightly larger than waferholder WH is used as wafer table WTB is different from the firstembodiment previously described (FIG. 2), however, the otherconfiguration and the like is similar to the first embodiment.Accordingly, the description below will be made focusing on thisdifference, and in order to avoid redundancy, the same referencenumerals will be used for the same or similar sections and a detaileddescription thereabout will be omitted. Incidentally, the size of wafertable WTB in the second embodiment is almost the same as wafer table WTBshown in FIGS. 4A to 4C.

In the second embodiment as well, encoder main bodies 16Ya, 16Yb, 16Xa,and 16Xb are placed on the ±Y side and the X side of wafer table WTB. Inthis case, when wafer table WTB is positioned as shown in FIG. 5A at aposition where the center of wafer W substantially coincides with thecenter of exposure area IA, positional relation of encoder main bodies16Ya and 16Yb are set so that the laser beams emitted from encoder mainbodies 16Ya and 16Yb are incident on a lower end section of a pair ofPBS18 arranged on the −Y side edge surface and the +Y side edge surfaceof wafer table WTB, respectively. Although there is a difference of theY-axis direction and the X-axis direction, the positional relationbetween encoder main bodies 16Xa and 16Xb is set similar to encoder mainbodies 16Ya and 16Yb.

Therefore, when wafer table WTB moves to the −Y side or the +Y side thanin FIG. 5A as shown in FIGS. 5B and 5C, respectively, light from one ofthe encoder main bodies 16Ya and 16Yb (encoder main body 16Yb in thecase of FIG. 5B, and encoder main body 16Ya in the case of FIG. 5C) willnot be incident on PBS18. Accordingly, in the embodiment, switching ofencoder main bodies 16Ya and 16Yb used for measurement of positionalinformation in the Y-axis direction is performed. More specifically,measurement of the positional information by one of the encoder mainbodies 16Ya and 16Yb can be switched to measurement of positionalinformation by the other encoder main body.

Therefore, in the second embodiment, before the laser beam from one ofencoder main bodies 16Ya and 16Yb moves off from PBS18, that is, whenwafer table WTB is located at a position where the laser beams fromencoder main bodies 16Ya and 16Yb can be simultaneously incident on apair of PBS18 arranged on the −Y side edge surface and the +Y side edgesurface of wafer table WTB, such as, for example, when wafer table WTBis at the position shown in FIG. 5A, a controller (not shown) performslinkage of measurement values of one of the encoder main bodies andmeasurement values of the other encoder main body. More specifically,the controller gives an initial value of a measurement value of theother encoder main body so that a measurement result of the otherencoder main body matches with a measurement result of the one encodermain body. This linkage process should be performed from the point wherethe laser beam of the other encoder main body which has moved away fromPBS18 is incident on PBS18 again until the laser beam from the oneencoder main body moves away from PBS18 (or until position measurementby the one encoder main body is switched to position measurement by theother encoder main body). Further, the linkage process does not have tobe performed simultaneously with the switching of the encoder main bodyused for position measurement, and the linkage process can be performedbefore the switching. Furthermore, the linkage process and the switchingof the encoder main body are each performed according to the position ofwafer table WTB in the Y-axis direction, or in other words, theexecution timing is decided according to the position of wafer table WTBin the Y-axis direction.

Further, the controller performs a similar process also for encoder mainbody 16Xa and 16Xb for X position measurement. More specifically, thecontroller gives an initial value of a measurement value as is describedabove before the laser beam from one of the encoder main body is nolonger incident on PBS18.

In the manner described above, the controller can constantly measurepositional information of wafer table WTB in the Y-axis direction withat least one of encoder main bodies 16Ya and 16Yb, and can alsoconstantly measure positional information of wafer table WTB in theX-axis direction with at least encoder main bodies 16Xa and 16Xb.Accordingly, the size of wafer table WTB can be reduced without anyserious problems.

As described above, according to the second embodiment, besides beingable to obtain an operation effect that is equal to the first embodimentpreviously described, since the controller performs linkage ofmeasurement values between encoder main bodies, position control ofwafer table WTB can be performed without any problems in particular evenwhen the size of wafer table WTB is reduced. Accordingly, the weight ofwafer table WTB can be reduced, which makes improvement of the positioncontrollability including the accuracy of positioning of wafer table WTBpossible, which in turn makes exposure with high precision possible.Further, when the weight of wafer table WTB is reduced, highacceleration can also be realized, which leads to an expectation in animprovement in the throughput of the exposure apparatus.

Incidentally, also in the second embodiment described above, for thesake of convenience, a pair of encoder main bodies for Y positionmeasurement and a pair of encoder main bodies for X position measurementwhose measurement points were set at the same position were arranged,however, the present invention is not limited to this, and in the caseof measuring yawing of wafer table WTB (θz rotation), at least two pairsor more of one of the encoder main bodies for Y positional measurementand X positional measurement can be arranged. In this case, the twopairs of encoder main bodies can be arranged so that the lights emittedfrom each of the encoder main bodies are incident on positions of anequal distance with the center of exposure area IA in between.

Further, also in the second embodiment above, the −Y side edge surfaceand the +Y side edge surface of wafer table WTB can be inclined at apredetermined angle (−θ) with respect to the XZ plane and the −X sideedge surface and the +X side edge surface of wafer table WTB can beinclined at a predetermined angle (−θ) with respect to the YZ plane, asshown in FIG. 4A and the like. In this case, the size of wafer table WTBcan be further reduced, and the range in which position measurement bythe encoder can be performed can be expanded. As well as thedescriptions above, also in the second embodiment, a configurationsimilar to other modified examples in the first embodiment previouslydescribed can be applied.

A Third Embodiment

Next, a third embodiment of the present invention will be described,referring to FIGS. 6A to 6C. The third embodiment is different on thepoints where the laser beam is incident on wafer table WTB from theupper surface side, and along with this, PBS18 is not arranged on theedge surface of wafer table WTB, from the first and second embodimentsin which the laser beams for measurement were incident on wafer tableWTB from the side surface, however, the configuration and the like ofother sections are similar to the first embodiment previously described.In the description below, the different points will be mainly described,and as for the configuration or the like of the same or similarsections, the same reference numerals will be used and a detaileddescription thereabout will be omitted.

In the third embodiment, in order to make a laser beam for measurementbe incident from the upper surface of wafer table WTB, a pair ofpolarization separation/composite members 49A and 49B is placed abovewafer table WTB in symmetry to an optical axis AX, as shown FIG. 6A.

Polarization separation/composite members 49A and 49B are fixed abovewafer table WTB in the vicinity of each of the encoder main bodies 16Yaand 16Yb, by a support member (not shown). Polarizationseparation/composite member 49A includes a cube type polarization beamsplitter 28A, and a reflecting mirror 30AB fixed to the surface ofpolarization beam splitter 28A positioned on the lowest side (the −Zside). Similarly, polarization separation/composite member 49B includesa polarization beam splitter 28B and a reflecting mirror 30B, and isconfigured in the same manner as polarization separation/compositemember 49A.

In polarization separation/composite members 49A and 49B, the enteringlaser beams from encoder main bodies 16Ya and 16Yb are each separatedinto a polarized component which passes through polarization beamsplitters 28A and 28B (for example, to be referred to as a firstpolarized component), and a polarized component which is reflected (forexample, to be referred to as a second polarized component) by thepolarization beam splitters. Then, the reflected polarized components(the second polarized components) are reflected by reflecting mirrors30A and 30B, and are reflected by beam splitters 28A and 28B again, andthen return to encoder main bodies 16Ya and 16Yb. More specifically,polarization separation/composite members 49A and 49B perform a functionsimilar to PBS18 that was previously described in the first and secondembodiments. Accordingly, also in the third embodiment, positionmeasurement can be performed similar to the first and second embodimentsdescribed above.

Further, in the third embodiment, because one side of wafer table WTB isaround three times the diameter of wafer W as in the first embodiment asshown in FIG. 6A, even if wafer table WTB moves within a range betweenthe position shown in FIG. 6B and the position shown in FIG. 6C, laserbeams for measurement from encoder main bodies 16Ya and 16Yb are made tobe constantly incident on wafer table WTB. Accordingly, positionalinformation of wafer table WTB in the Y-axis direction can constantly bemeasured, using the two encoder main bodies 16Ya and 16Yb. Therefore, ina controller (not shown), the Y position of wafer table WTB can becomputed with high precision, based on an average value of thesemeasurement results (coordinate values).

Incidentally, although it is omitted in the drawings, on the +X side ofexposure area IA, an encoder main body 16Xa is arranged as in the firstand second embodiments described above, and an encoder main body 16Xb isarranged on the −X side. Further, also in the vicinity of encoder mainbodies 16Xa and 16Xb, polarization separation/composite members similarto polarization separation/composite members 49A and 49B described aboveare arranged, and position measurement in the X-axis direction isperformed in a manner similar to the position measurement in the Y-axisdirection. Accordingly, a highly precise measurement can be performedalso for the position of wafer table WTB in the X-axis direction.

As described above, according to the third embodiment, positionmeasurement of wafer table WTB can be performed with high precision asin the first embodiment, therefore, by driving wafer table WTB based onthe measurement results, positioning with high precision can beperformed, which makes it possible to perform exposure with highprecision.

Incidentally, in the third embodiment above, the case has been describedwhere one side of wafer table WTB was set to around three times thediameter of wafer W as in the first embodiment, however, the presentinvention is not limited to this, and wafer table WTB can be set to asize slightly larger than wafer W, as in the second embodiment. In thiscase, as in the second embodiment described above, by performing alinkage of measurement by the two encoder main bodies for the X-axis andY-axis directions (for example, giving an initial value of a measurementvalue of the other encoder main body so that a measurement result of oneencoder main body matches a measurement result of the other encoder mainbody), the position of wafer table WTB can be constantly measured. Withthe arrangement above, the size and weight of wafer table WTB can bereduced without any problems, therefore, also from this point, a highlyprecise positioning of wafer table WTB can be achieved.

Incidentally, in the third embodiment above, for example, in the case ofmeasuring yawing (the θz rotation) of wafer table WTB as in the firstand second embodiments, at least one of the encoder main body for Xposition measurement and the encoder main body for Y positionmeasurement can be arranged in two or more pairs. Further, in the thirdembodiment, a configuration similar to each of the modified examplesdescribed earlier in the first embodiment can also be applied.

A Fourth Embodiment

Next, a fourth embodiment of the present invention will be described,referring to FIG. 7.

FIG. 7 shows a planar view of an exposure apparatus 100′ related to thefourth embodiment whose arrangement is partially omitted.

Exposure apparatus 100′ includes a main body chamber 112, an exposureapparatus main section 100 a′ including wafer stage WST arranged in mainbody chamber 112, an alignment chamber 116 arranged in the vicinity ofmain body chamber 112, a measurement section 110 housed in alignmentchamber 116, a wafer exchange chamber 118 arranged on the −X side ofalignment chamber 116, and a wafer exchange section 120 arranged withinwafer exchange chamber 118.

In the inside of main body chamber 112, environmental conditions (suchas degree of cleanliness, temperature, pressure force and the like) aremaintained substantially constant.

Exposure apparatus main section 100 a′ has a configuration which issubstantially the same as the first embodiment (exposure apparatus 100in the first embodiment) previously described, and wafer stage WST issupported by levitation via a predetermined clearance with respect to abase BS1 arranged on a floor surface F by a magnetic levitationmechanism (or an air bearing) (not shown).

On wafer stage WST configuring exposure apparatus main section 100 a′, awafer holder WH1 is mounted. On the lower surface of wafer holder WH1, atwo-dimensional grating (not shown) is arranged. Further, in thevicinity of the grating, a mark for deciding the origin of the grating(hereinafter referred to as an “origin mark”) is arranged. This originmark is detectable by encoder main bodies 16Ya, 16Yb, 16Xa, and 16Xb ina state where wafer holder WH1 is mounted on wafer stage WST, andfurther, is also detectable by an alignment system ALG which will bedescribed later on.

Further, as in the second embodiment, for example, wafer table WTB isconfigured of a transparent plate-shaped member such as glass or thelike and the side surface on the +Y side and the −Y side extend in theX-axis direction as well as slant to an XZ plane, and the side surfaceon the +X side and the −X side extend in the Y-axis direction as well assling to a YZ plane, and on these side surfaces, a PBS (not shown) isarranged. Incidentally, unlike the second embodiment, the grating is notinstalled on the upper surface of wafer table WTB, however, a grating isinstalled on the rear surface of wafer holder WH1. By using thisgrating, the position of wafer holder WH1 in the XY plane can bemeasured as in each of the embodiments above with encoder main bodies16Ya, 16Yb, 16Xa, and 16Xb. Incidentally, the rear surface of waferholder WH1 can be covered with a protective member (e.g., a cover glass,a film or the like).

Incidentally, instead of wafer holder WH1, wafer table WTB can also holdwafer holders WH2 and WH3 in FIG. 7. In the embodiment, by usinggratings installed on the rear surfaces of wafer holders WH2 and WH3held by wafer table WTB, the position of wafer holders WH2 and WH3 inthe XY plane can be measured by encoder main bodies 16Ya, 16Yb, 16Xa,and 16Xb.

In the inside of alignment chamber 116, environmental conditions (suchas degree of cleanliness, temperature, pressure force and the like) aremaintained substantially constant separately with main body chamber 112previously described.

Measurement section 110 includes a base BS2 arranged on floor surface Findependent from base BS1, a first holder holding member 22 arranged onbase BS2, an alignment system ALG, and an alignment stage AST fordriving alignment system ALG two-dimensionally on base BS2.Incidentally, although it is not shown, for example, base BS2 is placedon floor surface F (or on a base plate) via four vibration isolationunits.

The first holder holding member 22 has a rough square shape in a planarview, and in FIG. 7, supports wafer holder WH2, which can hold wafer W,on its upper surface. This wafer holder WH2 has a configuration similarto wafer holder WH1 previously described, and has a two-dimensionalgrating arranged on the rear surface. Incidentally, instead of waferholder WH2, the first holder hold member 22 can also support waferholders WH1 and WH3 in FIG. 7.

Although it is omitted in FIG. 7, alignment stage AST holds alignmentsystem ALG, and can be moved two-dimensionally above the first holderholding member 22, for example, by an X linear motor for drive in theX-axis direction and a Y-axis linear motor for drive in the Y-axisdirection. This allows a detection area of alignment system ALG to bemoved on the wafer, and a plurality of alignment marks can be detectedon the wafer.

As alignment system ALG, an alignment system is employed, for example,which includes an optical system, an illumination system including alight source connected to the optical system, and a photodetectionsystem including a CCD. Incidentally, as for the illumination system ofalignment system ALG, it does not have to be moved by alignment stageAST and can be arranged external to alignment stage AST, connected by anoptical fiber or the like. Incidentally, the arrangement is not limitedto this, and a relay optical system including a mirror and the likewhich transmits a beam from a light source arranged outside to anoptical system of alignment system ALG can also be used. Incidentally,alignment system ALG is not limited to a sensor by the image processingmethod, and other sensors of various methods can also be used. Further,it is desirable that the cables and the like connected to alignmentstage AST and alignment system ALG do not interfere with the movement ofalignment stage AST.

Position of alignment system ALG in the XY plane is measured using ameasurement unit (e.g. an interferometer or an encoder), and thecontroller (not shown) computes the position of the alignment marksarranged on the wafer, based on the position of alignment system ALGmeasured by the measurement unit and detection results by alignmentsystem ALG. Further, alignment system ALG detects the origin markarranged on wafer holder WH2 (or wafer holders WH1 and WH3), and thecontroller (not shown) computes the positional relation between theorigin mark and the alignment marks.

In the inside of wafer chamber 118, environmental conditions (such asdegree of cleanliness, temperature, pressure force and the like) aremaintained substantially constant separately with main body chamber 112and alignment chamber 116 previously described.

Wafer exchange unit 120 includes a base BS3 arranged on floor surface Fin wafer exchange chamber 118 independent from base BS1 and base BS2previously described, and a second holder holding member 24 arranged onbase BS3. In FIG. 7, wafer W is held via wafer holder WH3 on secondholder holding member 24. Wafer holder WH3 has a configuration similarto wafer holders WH1 and WH2 previously described, and has atwo-dimensional grating arranged on the rear surface. Incidentally,instead of wafer holder WH3, wafer holders WH1 and WH2 of FIG. 7 canalso be mounted on second holder hold member 24.

Furthermore, in the embodiment, a holder carrier unit (not shown) thatcarries wafer holders WH1 to WH3 between wafer stage WST, the firstholder holding member 22, and the second holder holding member 24 isarranged.

In exposure apparatus 100′ of the embodiment that has the configurationdescribed above, the following operation is performed. Incidentally, theoperation described below is performed by the controller (not shown),however, to avoid complication in the description, details related tothe controller will be omitted.

First of all, loading (in the case a wafer that has undergone exposureis held, exchange to a new wafer) of a wafer to wafer holder WH3 held bythe second holder holding member 24 of wafer exchange unit 120 isperformed.

Then, wafer holder WH3 which holds wafer W is carried from waferexchange unit 120 by the holder carrier unit (not shown), and waferholder WH1 on wafer stage WST is carried to wafer exchange unit 120 andis held by second holder holding member 24. And then, wafer holder WH2on the first holder holding member 22 is carried onto wafer stage WST1,and wafer holder WH3 carried from wafer exchange unit 120 is carriedonto the first holder holding member 22. Hereinafter, such carriageoperation of the wafer holders will be referred to as a holdercirculation operation.

Next, in measurement section 110, alignment of the wafer held by waferholder WH3 on the first holder holding member 22 is performed. In thisalignment, alignment system ALG is driven two-dimensionally by alignmentstage AST, and the alignment marks (e.g., eight) formed on the wafer aredetected. Further, detection of the origin mark arranged on wafer holderWH3 is also performed, and the positional relation between the originmark and the alignment marks is also computed.

Meanwhile, in wafer exchange unit 120, in parallel with the alignmentoperation described above, wafer W is loaded on wafer holder WH1 mountedon the second holder holding member 24.

Then, the holder circulation operation previously described isperformed, and wafer holder WH3 is mounted on wafer table WTB, waferholder WH1 is mounted on the first holder holding member 22, and waferholder WH2 is mounted on the second holder holding member 24.

Then, in exposure apparatus main section 10 a′, the origin mark of waferholder WH3 mounted on wafer table WTB is detected by encoder main bodies16Ya, 16Yb, 16Xa, and 16Xb, and from the detection result and thepositional relation between the alignment marks and the origin mark ofwafer holder WH3 measured using alignment system ALG, coordinate valuesof the alignment marks in an exposure coordinate system are calculated.And then, using the coordinate values of the alignment marks which havebeen calculated, EGA (Enhanced Global Alignment) as in the one disclosedin, for example, U.S. Pat. No. 4,780,617 description and the like isperformed, and based on the results of the EGA, exposure operation of aplurality of shot areas on wafer W is performed.

Further, in parallel with the exposure operation in exposure apparatusmain section 100 a′, in measurement section 110, an alignment operationto wafer W on wafer holder WH1 is performed in the same manner as in theprevious description, and in wafer exchange unit 120, loading (in thiscase, wafer exchange) of a wafer to wafer holder WH2 is performed.

Hereinafter, the wafer circulation operation and each of the operationsperformed in exposure apparatus main section 100 a′, measurement section110, and wafer exchange unit 120 are repeatedly performed, and exposureoperation to a predetermined number of wafers is performed.

As discussed above, according to the fourth embodiment, wafer holdersWH1 to WH3 are freely detachable with respect to wafer table WTB, andbecause the origin (origin mark) is arranged on wafer holders WH1 toWH3, even if alignment operation of wafer W is performed in a statewhere wafer holders WH1 to WH3 are detached from wafer table WTB andthen are mounted on wafer table WTB, the alignment result can be usedwith the origin (origin mark) serving as a reference, therefore, analignment operation can be performed on one wafer and an exposureoperation can be performed on the other wafer in parallel. Accordingly,high throughput can be achieved.

Further, also in the embodiment, because position measurement of wafertable WTB is performed using encoder main bodies 16Ya, 16Yb, 16Xa, and16Xb similar to the first to third embodiments, positioning of wafertable WTB with high precision can be achieved, which in turn makes itpossible to perform exposure with high precision.

Incidentally, in the fourth embodiment above, the case has beendescribed where exposure apparatus 100′ is equipped with exposureapparatus main section 100 a′ measurement section 110, and waferexchange unit 120, however, the present invention is not limited tothis, and exposure apparatus 100′ can be equipped with only exposureapparatus main section 100 a′ and measurement section 110. Further, aswell as these configurations, in the case the wafer holder is freelydetachable to wafer table WTB and alignment on the wafer on the waferholder is to be performed without using wafer table WTB, theconfiguration in the fourth embodiment described above in which agrating is arranged on the rear surface of the wafer holder is suitable.

Incidentally, in the fourth embodiment above, the case has beendescribed where alignment of a fixed wafer is performed using a movablealignment system ALG, however, the present invention is not limited tothis, and a configuration in which alignment system ALG is fixed and thefirst holder holding member 22 holding the wafer holder on which thewafer is mounted is movable within the XY plane can be employed.

Incidentally, in the fourth embodiment above, the case has beendescribed where the exposure apparatus main section, the measurementsection, and the wafer exchange section are placed in separate chambers,however, the present invention is not limited to this, and each sectioncan all be placed in one chamber, or two of the sections described abovecan be placed in the same chamber.

Incidentally, in the fourth embodiment above, the encoder system and thewafer table of the second embodiment are employed, however, the encodersystem and the wafer table of the first or third embodiment can also beemployed. Further, in the fourth embodiment above, in the case ofmeasuring the θz rotation of wafer table WTB, at least one of theencoder main bodies for X-axis measurement and Y-axis measurement can bechanged from one pair to two pairs. Further, in the fourth embodimentabove, a configuration similar to the configuration in each of themodified examples in the first to third embodiments above can also beapplied.

A Fifth Embodiment

Next, a fifth embodiment of the present invention will be described,referring to FIGS. 8 and 9. FIG. 8 shows a projection optical system PLof the exposure apparatus related to the fifth embodiment, and thecomponents below the projection optical system. Incidentally, thecomponents above projection optical system PL are similar to the firstembodiment shown in FIG. 1, therefore, the drawing and descriptionthereabout will be omitted. Further, projection optical system PL shownin FIG. 8 and the configuration below the projection optical system canbe employed without any changes in exposure apparatus 100 in FIG. 1.

In the fifth embodiment, projection optical system PL is supported by aprojection optical system base platform (barrel platform (hereinafterreferred to as base platform)) 32, which is supported by a plurality of(e.g., three) supporting columns 34 on a floor surface F. The lower endof projection optical system PL is inserted in a circular opening 32 awhich is formed in the center of base platform 32, and projectionoptical system PL is supported by base platform 32 via a flange FLGwhich is arranged slightly below the center in the height direction.Incidentally, as disclosed in, for example, the pamphlet ofInternational Publication No. 2006/038952, projection optical system PL(and base platform 32) can be supported in a suspended state withrespect to a base member and the like on which a reticle stage isplaced.

On the lower surface of base platform 32, a wafer stage base platform BSis supported by suspension via a suspension support member 36.Incidentally, wafer stage base platform BS can be supported using aplurality of support members 36, without being supported by onesuspension support member 36 as in FIG. 8.

Above wafer stage base platform BS, wafer stage WST is movablysupported, for example, by magnetic force, by levitation in anon-contact manner. Wafer stage base platform BS includes a thickplate-shaped base platform main body 42, and a cover member 38consisting of a glass plate or the like arranged on the upper surface ofbase platform main body 42. Further, on the upper surface of baseplatform main body 42, a recessed section is formed (not shown), and inthe recessed section, an encoder main body ENC for Y positionmeasurement and an encoder main body for X position measurement arearranged. However, the encoder main body for X position measurement isomitted in the drawing.

In wafer stage WST, a configuration different from the first to fourthembodiments is employed. More specifically, wafer stage WST is not madeup of a wafer table and a stage main section, and is formed as anintegral object, for example, by a rectangular solid shaped glassmember. As an example, wafer stage WST is made of the same material asthe transmission member of wafer table WTB previously described.Although it is not shown, this wafer stage WST is driven freely(including rotation in the θz direction) in the XY plane, for example,by a wafer stage drive system including a linear motor or a planarmotor.

Further, on the upper surface of wafer stage WST, a two-dimensionalgrating 24 is installed (refer to FIG. 9) similar to wafer table WTB inthe first to third embodiments, and its upper surface is covered with acover glass. Incidentally, grating 24 can be arranged on the lowersurface of wafer holder WH, as in the fourth embodiment.

FIG. 9 shows Encoder main body ENC, along with wafer stage WST. In theembodiment, the encoder main body is placed below wafer stage WST, and alaser beam for measurement is made to enter the inside of wafer stageWST from its lower surface so that the beam is irradiated on grating 24.The irradiation point (that is, the measurement point of the encodermain body) of the laser beam for measurement coincides with point IAa,which is right under the center of exposure area IA.

Encoder main body ENC includes a light irradiation section 210 a and alight-receiving section 210 b. Light irradiation section 210 a includesa semiconductor laser 212, a lens 214, a polarization beam splitter BS1,a pair of reflecting mirrors 216 a and 216 b, a pair of lenses 218 a and218 b, a pair of λ/4 plates 220 a and 220 b, and a pair of planarmirrors 222 a and 222 b. Further, light-receiving section 210 b includesa semi-transmissive mirror (a half mirror) 224, a pair of polarizationbeam splitters BS2 and BS3, a λ/4 plate 226, and four photodetectors 228a, 228 b, 228 c, and 228 d.

In the embodiment, in encoder main body ENC, a laser beam emitted fromsemiconductor laser 212 is incident on polarization beam splitter BS1via lens 214, and is split by polarization (separated to an s-polarizedlight component and a p-polarized light component) by polarization beamsplitter BS1 into two laser beams. And, one of the laser beams (thepolarized component reflected by polarization beam splitter BS1) isreflected off reflecting mirror 216 a, and then is incident on waferstage WST and reaches grating 24 on the upper surface of wafer stageWST. The irradiation point of the laser beam is to be point IAa rightunder the center of exposure area IA. Meanwhile, the other laser beam(the polarized component which has passed through polarization beamsplitter BS1) is reflected by reflecting mirror 216 b, and is incidenton wafer stage WST and reaches grating 24 on the upper surface of waferstage WST. The irradiation point of this laser beam is also point IAa.Then, the light (a diffraction light whose order is a first order or ahigher order of the same reference numeral) diffracted with the gratingof grating 24 whose periodic direction is the Y-axis direction isreflected off each of the planar mirrors 222 a and 222 b, via lenses 218a and 218 b and λ/4 plates 220 a and 220 b. And then, by tracing thesame optical path as when entering in the reversed direction, each ofthe reflected lights are incident on polarization beam splitter BS1,after passing through λ/4 plates 220 a and 220 b again.

In this case, because the lights which have reached polarization beamsplitter BS1 each pass λ/4 plates 220 a and 220 b twice, thepolarization direction is rotated by 90° from the entering point oftime. Accordingly, one of the lights (that is, the polarized componentreflected by polarization beam splitter BS1) via reflecting mirror 216 apasses through polarization beam splitter BS1, and the other light (thepolarized component which has passed through polarization beam splitterBS1) via reflecting mirror 216 b is reflected by polarization beamsplitter BS1. More specifically, these light are synthesized coaxiallyat polarization beam splitter BS1, and then heads towardsemi-transmissive mirror 224.

Then, the beam that has reached semi-transmissive mirror 224 is dividedin two, and one of the beams reaches polarization beam splitter BS3, andthe other beam reaches polarization beam splitter BS2 via λ/4 plate 226.

The beam (interference light) separated by polarization at polarizationbeam splitter BS2 each reaches photodetectors 228 a and 228 b, and theoptical intensity is converted into electrical signals in each of thephotodetectors 228 a and 228 b. Further, the beam (interference light)separated by polarization at polarization beam splitter BS3 each reachesphotodetectors 228 c and 228 d, and the optical intensity is convertedinto electrical signals in each of the photodetectors 228 c and 228 d.

The electrical signals output in the manner described above are inputinto the controller (not shown), which measures positional informationof wafer stage WST in the Y-axis direction based on the electricalsignals.

Incidentally, the encoder main body for X position measurement is alsoconfigured similarly, and the positional information of wafer stage WSTin the X-axis direction is measured using the diffraction lightdiffracted by the grating of grating 24 whose periodic direction is inthe X-axis direction. Further, the encoder main body is arranged so thatits optical axis is substantially orthogonal to the upper surface (thegrating surface on which grating 24 is formed) of wafer stage WST.Incidentally, the configuration of the encoder main body is not limitedto the ones described above, and encoder main bodies having otherconfigurations can also be adopted, and depending on the configuration,the optical axis does not have to be arranged orthogonal to the uppersurface of wafer stage WST.

As described above, according to the fifth embodiment, because grating24 is arranged on the upper surface of the wafer stage, a highly precisemeasurement of wafer stage WST can be performed similar to the first tofourth embodiments.

Incidentally, in each of the embodiments above, the laser beam formeasurement emitted from each encoder main body was designed to beincident on grating 24 at point IAa right under the center of exposurearea IA, however, the present invention is not limited to this, and whensuch a setting is difficult, the laser beam can be designed to beincident on grating 24 at another point which is different from pointIAa. Further, a position of the measurement point can be made differentin encoder main body for X position measurement and encoder main bodyfor Y position measurement. Furthermore, a plurality of at least one ofthe encoder main body for X position measurement and the encoder mainbody for Y position measurement can be arranged. In this case, aposition of the measurement point of the plurality of encoder mainbodies whose measurement direction is the same can be made different. Ofthe plurality of encoder main bodies, positional information of waferstage WST in the θz direction can be measured by at least two encodermain bodies whose position of the measurement point differs in adirection besides the measurement direction.

Incidentally, in each of the embodiments above, at least a part of wafertable WTB is configured by a material (such as synthetic quartz) throughwhich the laser beam for measurement of the encoder system could pass,however, the present invention is not limited to this, and, for example,wafer table WTB can be configured by a hollow frame member. In thiscase, a transmission member can be arranged in an opening section of theframe member to seal the inside, or the temperature inside can be madeadjustable. Including the case where the wafer table is configured by ahollow frame member, in each of the embodiments above, a configurationcan be employed where of the components of the encoder main body, asection which becomes a heat source (such as a light source, a detectorand the like) and a section which does not become a heat source (such asan optical system) are separated, and both sections are connected by anoptical fiber.

Further, in the first to third and fifth embodiments above, grating 24was arranged on the upper surface of wafer table WTB or wafer stage WST,however, the present invention is not limited to this, and, for example,the grating can be arranged on the lower surface of the cover glass oron the rear surface of the wafer holder. Furthermore, instead ofarranging a protective member such as a cover glass, for example, thewafer holder can be used as a substitute.

Incidentally, in each of the embodiments above, the case has beendescribed where the exposure apparatus is equipped with a single waferstage, however, the present invention is not limited to this, and thepresent invention can also be applied to an exposure apparatus equippedwith a plurality of wafer stages, as disclosed in, for example, U.S.Pat. No. 6,590,634 description, U.S. Pat. No. 5,969,441 description,U.S. Pat. No. 6,208,407 description and the like. Further, for example,as disclosed in U.S. Pat. No. 6,897,963 description, the presentinvention can also be applied to an exposure apparatus equipped with awafer stage, and a stage unit including a measurement stage which canmove independently from the wafer stage.

Incidentally, the present invention can also be applied to a liquidimmersion exposure apparatus whose details are disclosed in, forexample, the pamphlet of International Publication No. 2004/053955 andthe corresponding U.S. Patent Application Publication No. 2005/0259234description and the like.

Further, the projection optical system in the exposure apparatus of eachof the embodiments above is not limited only to a reduction system, butalso can be either an equal magnifying system or a magnifying system,and the projection optical system is not limited only to a dioptricsystem, but also can be either a catoptric system or a catodioptricsystem, and the projected image can be either an inverted image or anupright image. Furthermore, exposure area IA previously described is anon-axis area including optical axis AX within the field of projectionoptical system PL, however, it can also be an off-axis area that doesnot include optical axis AX similar to the in-line type catodioptricsystem whose details are disclosed in, for example, the pamphlet ofInternational Publication No. 2004/107011. Further, the shape ofexposure area IA is not limited to a rectangle, and, for example, acircular arc, a trapezoid, or a parallelogram is also preferable.

Further, illumination light IL is not limited to the ArF excimer laserbeam (wavelength 193 nm), and illumination light IL can also be anultraviolet light such as a KrF excimer laser beam (wavelength 248 nm)or a vacuum-ultraviolet light such as an F₂ laser beam (wavelength 157nm). Further, as disclosed in, for example, U.S. Pat. No. 7,023,610description, a harmonic wave, which is obtained by amplifying asingle-wavelength laser beam in the infrared or visible range emitted bya DFB semiconductor laser or fiber laser as vacuum ultraviolet light,with a fiber amplifier doped with, for example, erbium (or both erbiumand ytteribium), and by converting the wavelength into ultraviolet lightusing a nonlinear optical crystal, can also be used.

Further, in the embodiment above, illumination light IL of the exposureapparatus is not limited to the light having a wavelength equal to ormore than 100 nm, and it is needless to say that the light having awavelength less than 100 nm can be used. For example, the presentinvention can be preferably applied to an EUV exposure apparatus thatgenerates an EUV (Extreme Ultraviolet) light in a soft X-ray region(e.g. a wavelength range from 5 to 15 nm) with an SOR or a plasma laserserving as a light source, and uses a total reflection reduction opticalsystem designed under the exposure wavelength (e.g. 13.5 nm) and areflective mask. Besides such an apparatus, the present invention canalso be applied to an exposure apparatus that uses charged particlebeams such as an electron beam or an ion beam.

Further, in each of the embodiments above, a transmissive type mask(reticle), which is a transmissive substrate on which a predeterminedlight shielding pattern (or a phase pattern or a light attenuationpattern) is formed, is used. Instead of this reticle, however, as isdisclosed in, for example, U.S. Pat. No. 6,778,257 description, anelectron mask (which is also called a variable shaped mask, an activemask or an image generator, and includes, for example, a DMD (DigitalMicromirror Device) that is a type of a non-emission type image displaydevice (spatial light modulator) or the like) on which alight-transmitting pattern, a reflection pattern, or an emission patternis formed according to electronic data of the pattern that is to beexposed can also be used.

Further, as disclosed in, for example, the pamphlet of InternationalPublication No. 2001/035168, the present invention can also be appliedto an exposure apparatus (lithography system) that forms line-and-spacepatterns on a wafer by forming interference fringes on the wafer.

Moreover, as disclosed in, for example, U.S. Pat. No. 6,611,316description, the present invention can also be applied to an exposureapparatus that synthesizes two reticle patterns via a projection opticalsystem and almost simultaneously performs double exposure of one shotarea by one scanning exposure.

Further, an apparatus that forms a pattern on an object is not limitedto the exposure apparatus (lithography system) described above, and forexample, the present invention can also be applied to an apparatus thatforms a pattern on an object by an ink-jet method.

Incidentally, an object on which a pattern is to be formed (an objectsubject to exposure to which an energy beam is irradiated) in each ofthe embodiments above is not limited to a wafer, but may be otherobjects such as a glass plate, a ceramic substrate, a film member, or amask blank.

The use of the exposure apparatus is not limited only to the exposureapparatus for manufacturing semiconductor devices, but the presentinvention can also be widely applied to an exposure apparatus fortransferring a liquid crystal display device pattern onto a rectangularglass plate and an exposure apparatus for producing organic ELs, thinmagnetic heads, imaging devices (such as CCDs), micromachines, DNAchips, and the like. Further, the present invention can be applied notonly to an exposure apparatus for producing microdevices such assemiconductor devices, but can also be applied to an exposure apparatusthat transfers a circuit pattern onto a glass plate or silicon wafer toproduce a mask or reticle used in a light exposure apparatus, an EUVexposure apparatus, an X-ray exposure apparatus, an electron-beamexposure apparatus, and the like.

Incidentally, the movable body system of the present invention can beapplied not only to the exposure apparatus, but can also be appliedwidely to other substrate processing apparatuses (such as a laser repairapparatus, a substrate inspection apparatus and the like), or toapparatuses equipped with a movable body such as a stage that moveswithin a two-dimensional plane such as a position setting apparatus forspecimen or a wire bonding apparatus in other precision machines.

Further, the exposure apparatus (the pattern forming apparatus) of theembodiment above is manufactured by assembling various subsystems, whichinclude the respective constituents that are recited in the claims ofthe present application, so as to keep predetermined mechanicalaccuracy, electrical accuracy and optical accuracy. In order to securethese various kinds of accuracy, before and after the assembly,adjustment to achieve the optical accuracy for various optical systems,adjustment to achieve the mechanical accuracy for various mechanicalsystems, and adjustment to achieve the electrical accuracy for variouselectric systems are performed. A process of assembling varioussubsystems into the exposure apparatus includes mechanical connection,wiring connection of electric circuits, piping connection of pressurecircuits, and the like among various types of subsystems. Needless tosay, an assembly process of individual subsystem is performed before theprocess of assembling the various subsystems into the exposureapparatus. When the process of assembling the various subsystems intothe exposure apparatus is completed, a total adjustment is performed andvarious kinds of accuracy as the entire exposure apparatus are secured.Incidentally, the making of the exposure apparatus is preferablyperformed in a clean room where the temperature, the degree ofcleanliness and the like are controlled.

Incidentally, the disclosures of the various publications, the pamphletsof the International Publications, and the U.S. Patent ApplicationPublication descriptions and the U.S. patent descriptions that are citedin the embodiment above and related to exposure apparatuses and the likeare each incorporated herein by reference.

Next, an embodiment of a device manufacturing method in which theexposure apparatus (pattern forming apparatus) described above is usedin a lithography process will be described.

FIG. 10 shows a flowchart of an example when manufacturing a device (asemiconductor chip such as an IC or an LSI, a liquid crystal panel, aCCD, a thin film magnetic head, a micromachine, and the like). As isshown in FIG. 10, first of all, in step 401 (a design step), functionand performance design of device (such as circuit design ofsemiconductor device) is performed, and pattern design to realize thefunction is performed. Then, in step 402 (a mask making step), a mask(reticle) is made on which the circuit pattern that has been designed isformed. Meanwhile, in step 403 (a wafer fabrication step), wafers aremanufactured using materials such as silicon.

Next, in step 404 (a wafer processing step), the actual circuit and thelike are formed on the wafer by lithography or the like in a manner thatwill be described later, using the mask (reticle) and the wafer preparedin steps 401 to 403. Then, in step 405 (a device assembly step), deviceassembly is performed using the wafer processed in step 404. Step 405includes processes such as the dicing process, the bonding process, andthe packaging process (chip encapsulation), and the like when necessary.

Finally, in step 406 (an inspection step), tests on operation,durability, and the like are performed on the devices made in step 405.After these steps, the devices are completed and shipped out. Afterthese processes, the devices are completed and are shipped out.

FIG. 11 is a flowchart showing a detailed example of step 404 describedabove. In FIG. 11, in step 411 (an oxidation step), the surface of thewafer is oxidized. In step 412 (a CDV step), an insulating film isformed on the wafer surface. In step 413 (an electrode formation step),an electrode is formed on the wafer by deposition. In step 414 (an ionimplantation step), ions are implanted into the wafer. Each of the abovesteps 411 to step 414 constitutes the preprocess in each step of waferprocessing, and the necessary processing is chosen and is executed ateach stage.

When the above-described preprocess ends in each stage of waferprocessing, post-process is executed as follows. First of all, in thepost-process, first in step 415 (a resist formation step), aphotosensitive agent is coated on the wafer. Then, in step 416 (anexposure step), the circuit pattern of the mask (reticle) is transferredon a wafer by the exposure apparatus (pattern formation apparatus) andthe exposure method (pattern formation method) described above. Next, instep 417 (a development step), the wafer that has been exposed isdeveloped, and in step 418 (an etching step), an exposed member of anarea other than the area where resist remains is removed by etching.Then, in step 419 (a resist removing step), when etching is completed,the resist that is no longer necessary is removed.

By repeatedly performing the pre-process and the post-process, multiplecircuit patterns are formed on the wafer.

By using the device manufacturing method of the embodiment describedabove, because the exposure apparatus (pattern formation apparatus) inthe embodiment above and the exposure method (pattern formation method)thereof are used in the exposure step (step 416), exposure with highthroughput can be performed while maintaining the high overlay accuracy.Accordingly, the productivity of highly integrated microdevices on whichfine patterns are formed can be improved.

While the above-described embodiments of the present invention are thepresently preferred embodiments thereof, those skilled in the art oflithography systems will readily recognize that numerous additions,modifications, and substitutions may be made to the above-describedembodiments without departing from the spirit and scope thereof. It isintended that all such modifications, additions, and substitutions fallwithin the scope of the present invention, which is best defined by theclaims appended below.

1. A movable body system, the system comprising: a movable body that ismovable substantially along a predetermined plane holding an object, andhas a grating placed along a plane on a rear surface side of the objectsubstantially parallel with the predetermined plane, and light that hasentered from the outside can proceed inside toward the grating; and ameasurement system that makes light enter the inside of the movable bodyfrom the outside, and measures positional information of the movablebody in a measurement direction in the predetermined plane by receivinglight including a reflected light from the grating.
 2. The movable bodysystem according to claim 1 wherein the measurement system makes thelight enter from a side surface of the movable body intersecting thepredetermined plane.
 3. The movable body system according to claim 2wherein the side surface of the movable body is made of an inclinedsurface which forms an acute angle or an obtuse angle with respect tothe predetermined plane, and the measurement system makes the lightenter perpendicularly to the inclined surface.
 4. The movable bodysystem according to claim 2 wherein the measurement system makes thelight enter from different side surfaces of the movable body, andpositional information of the movable body in the measurement directionis measured by receiving light including the reflected light from thegrating.
 5. The movable body system according to claim 4 wherein thedifferent side surfaces include two side surfaces of the movable bodythat extend in a first and second direction orthogonal in thepredetermined plane, and the measurement system includes a plurality ofmeasurement units which can measure positional information of themovable body in the first and second directions.
 6. The movable bodysystem according to claim 4 wherein the different side surfaces includea pair of side surfaces of the movable body which extends in the firstdirection within the predetermined plane, respectively, and themeasurement system includes a pair of measurement units which canmeasure positional information of the movable body in the samedirection.
 7. The movable body system according to claim 6 wherein themeasurement system can switch a measurement of positional information ofthe movable body by one of the pair of measurement units to ameasurement of positional information of the movable body by the otherof the pair of measurement units.
 8. The movable body system accordingto claim 7 wherein the measurement system performs switching of themeasurement unit used for measurement of the positional information,according to the position of the movable body in the second directionorthogonal to the first direction in the predetermined plane.
 9. Themovable body system according to claim 7, the system further comprising:a controller that sets an initial value of the other measurement unitwhen measurement of positional information of the movable body isswitched from one of the measurement unit of the pair to the other, sothat measurement results of the pair of measurement units match eachother.
 10. The movable body system according to claim 6 wherein the pairof measurement units has a measurement axis in the first direction atsubstantially the same position.
 11. The movable body system accordingto claim 4 wherein a plurality of lights that enter the inside of themovable body is irradiated on the same point in the predetermined plane.12. The movable body system according to claim 2 wherein the measurementsystem receives light which is reflected by the grating and also passesthrough the entering side surface of the light again.
 13. The movablebody system according to claim 2 wherein the measurement system detectsan interference light between light which enters the inside of themovable body via the side surface and is reflected by the grating andlight reflected by the side surface of the movable body.
 14. The movablebody system according to claim 2 wherein the measurement system has apolarization separation member arranged external to the movable bodythat separates the incident light by polarization, and detects aninterference light between one of a polarized component which passesthrough the polarization separation member and the side surface and theother polarized component reflected by the polarization separationmember.
 15. The movable body system according to claim 14 wherein thepolarization separation member is arranged on a side surface of themovable body.
 16. The movable body system according to claim 2 whereinthe side surface of the movable body is an inclined surface which formsan acute angle with a formation surface of the grating, and themeasurement system performs irradiation on the grating withoutreflecting the light inside the movable body.
 17. The movable bodysystem according to claim 2 wherein the side surface of the movable bodyis an inclined surface which forms an obtuse angle with a formationsurface of the grating, and the measurement system performs irradiationon the grating of the light which is reflected at least once inside themovable body.
 18. The movable body system according to claim 1 whereinthe measurement system makes the light enter from the upper surface ofthe movable body which is substantially parallel to the predeterminedplane.
 19. The movable body system according to claim 18 wherein themeasurement system includes a plurality of measurement units that makeeach of the lights enter from different directions in the predeterminedplane and can measure positional information of the movable body in thedifferent directions.
 20. The movable body system according to claim 18wherein the measurement system includes a pair of measurement unitswhich makes the lights enter in opposite ways to each othersubstantially along the same direction in the predetermined plane, andcan measure positional information of the movable body in the samedirection.
 21. The movable body system according to claim 18 wherein themeasurement system performs irradiation on the grating of the lightwhich is reflected at least once inside the movable body.
 22. Themovable body system according to claim 18 wherein the measurement systemincludes a polarization beam splitter which is placed above the movablebody and separates the incident light by polarization and makes one ofthe polarized components enter the inside of the movable body from theupper surface obliquely, and a reflection member which reflects theother polarized component separated by the polarization beam splitter,and detects an interference light between a reflected light from thegrating of the one polarized component and a reflected light from thereflection member of the other polarized component.
 23. The movable bodysystem according to claim 1 wherein the measurement system makes thelight obliquely enter the grating inside the movable body.
 24. Themovable body system according to claim 1 wherein in the measurementsystem, an entering direction of the light and a measurement directionof the positional information of the movable body are parallel in thepredetermined plane.
 25. The movable body system according to claim 1wherein the measurement system makes the light enter from the lowersurface of the movable body which is substantially parallel to thepredetermined plane.
 26. The movable body system according to claim 25wherein the measurement system includes an optical system arranged belowthe lower surface of the movable body and whose optical axis issubstantially orthogonal to the predetermined plane.
 27. The movablebody system according to claim 25 wherein the measurement system makes aplurality of lights enter the movable body from its lower surface andalso irradiates the lights at different points in the predeterminedplane.
 28. The movable body system according to claim 1 wherein lightthat enters the inside of the movable body is irradiated on apredetermined point where the movable body should be positioned in thepredetermined plane or in the vicinity of the point.
 29. The movablebody system according to claim 1 wherein the movable body includes aholding member which holds the object and also has the grating arrangedon its rear surface, and a table on which the holding member is mountedand where the light passes inside.
 30. The movable body system accordingto claim 29 wherein on one of the rear surface of the holding member andthe gratings, a reference point is arranged which serves as a referencefor a position in a plane parallel to the predetermined plane of theholding member.
 31. The movable body system according to claim 29wherein the holding member is freely detachable to the table.
 32. Themovable body system according to claim 31 wherein the movable body hasan electrostatic chuck mechanism which holds the holding member on thetable by suction.
 33. The movable body system according to claim 1wherein the movable body includes a transmission member on which thelight is incident and also has the grating formed on a surfacesubstantially parallel to the predetermined plane, and a holding memberthat holds the object and is also arranged on the surface side withrespect to the transmission member.
 34. The movable body systemaccording to claim 33 wherein the transmission member has the surfacecovered with the holding member or a member different from the holdingmember.
 35. A pattern formation apparatus, comprising: a movable bodysystem according to claim 1, in which for pattern formation to anobject, the object is held by the movable body.
 36. An exposureapparatus that forms a pattern on an object by an irradiation of anenergy beam, the apparatus comprising: a patterning unit that irradiatesthe energy beam on the object; and a movable body system according toclaim 1, wherein a movable body that holds the object of the movablebody system is driven for relative movement of the energy beam and theobject.
 37. The exposure apparatus according to claim 36 wherein themovable body includes a table through which light from the measurementsystem passes inside and a holding member that can hold the object andis arranged on the table, and the grating is formed on the table or theholding member.
 38. The exposure apparatus according to claim 36 whereinthe movable body includes a table through which light from themeasurement system passes inside and a holding member that can hold theobject and is arranged freely detachable to the table, and the apparatusfurther comprising: an alignment unit that measures a positionalrelation between the holding member detached from the table and theobject held by the holding member, whereby the movable body is drivenbased on a measurement result of the alignment unit and positionalinformation of the movable body measured by the measurement system, andthe energy beam is irradiated on the object held by the holding member.39. The exposure apparatus according to claim 36 wherein light thatenters the inside of the movable body is irradiated on a predeterminedpoint in an irradiation area of the energy beam.
 40. The exposureapparatus according to claim 36 wherein the predetermined point on whichthe light that enters the inside of the movable body is irradiated is anexposure center of the patterning unit. 41-58. (canceled)
 59. A devicemanufacturing method, the method comprising: exposing a substrate usingan exposure apparatus according to claim 36; and developing a substratewhich has been exposed.
 60. An exposure method in which an energy beamis irradiated on an object so as to form a predetermined pattern on theobject wherein a movable body that holds the object and also has agrating placed along a surface substantially parallel to a predeterminedplane on a rear surface side of the object, and in which light enteringfrom the outside can proceed toward the grating in the inside, is movedalong the predetermined plane, and light is made to enter the inside ofthe movable body from the outside, and positional information of themovable body in a measurement direction in the predetermined plane ismeasured by receiving light including a reflected light from thegrating.
 61. The exposure method according to claim 60 wherein the lightis made to enter from a side surface of the movable body whichintersects the predetermined plane.
 62. The exposure method according toclaim 61 wherein the side surface of the movable body is made of aninclined surface which forms an acute angle or an obtuse angle withrespect to the predetermined plane, and the light is made to enterperpendicularly with respect to the inclined surface.
 63. The exposuremethod according to claim 61 wherein the light is made to enter fromdifferent side surfaces of the movable body, and positional informationof the movable body in the measurement direction is measured byreceiving light including the reflected light from the grating.
 64. Theexposure method according to claim 63 wherein the different sidesurfaces include two side surfaces of the movable body that extend in afirst and second direction orthogonal in the predetermined plane, and aplurality of measurement units is used to measure positional informationof the movable body in the first and second directions.
 65. The exposuremethod according to claim 63 wherein the different side surfaces includea pair of side surfaces of the movable body which extends in the firstdirection within the predetermined plane, respectively, and theplurality of measurement units includes a pair of measurement unitswhich can measure positional information of the movable body in the samedirection.
 66. The exposure method according to claim 65 wherein ameasurement of positional information of the movable body by one of thepair of measurement units can be switched to a measurement of positionalinformation of the movable body by the other of the pair of measurementunits.
 67. The exposure method according to claim 66 wherein switchingof the measurement unit used for measurement of the positionalinformation is performed, according to the position of the movable bodyin the second direction orthogonal to the first direction in thepredetermined plane.
 68. The exposure method according to claim 66wherein an initial value of the other measurement unit is set whenmeasurement of positional information of the movable body is switchedfrom one of the measurement unit of the pair to the other, so thatmeasurement results of the pair of measurement units match each other.69. The exposure method according to claim 60 wherein light that entersthe inside of the movable body is irradiated on a predetermined point inan irradiation area of the energy beam.
 70. The exposure methodaccording to claim 60 wherein the predetermined point on which the lightthat enters the inside of the movable body is irradiated is an exposurecenter.
 71. A device manufacturing method, the method comprising:exposing a substrate using an exposure method according to claim 60; anddeveloping a substrate which has been exposed.
 72. An exposure method inwhich an energy beam is irradiated on an object so as to form apredetermined pattern on the object wherein a first and second lightsare made to enter the inside of a movable body that holds the object andcan move in a predetermined plane, and has a grating placed along asurface substantially parallel to the predetermined plane on the rearsurface side of the object, and positional information of the movablebody in the measurement direction in the predetermined plane is measuredusing a first and second measurement unit which receive the lightproceeding in the inside and is reflected by the grating, and ameasurement of the positional information of the movable body using oneof the first and second measurement units is switched to a measurementof the positional information of the movable body using the othermeasurement unit of the first and second measurement units.
 73. Theexposure method according to claim 72 wherein the first and secondlights are made to enter the inside of the movable body in opposite waysto each other substantially along the same direction in thepredetermined plane.
 74. The exposure method according to claim 73wherein the first light is made to enter from one of the pair of sidesurfaces of the movable body each extending in the first direction inthe predetermined plane and the second light is made to enter from theother of the pair.
 75. The exposure method according to claim 74 whereinswitching of the measurement unit used for measurement of the positionalinformation is performed, according to the position of the movable bodyin the second direction orthogonal to the first direction in thepredetermined plane.
 76. The exposure method according to claim 72wherein an initial value of the other measurement unit is set whenmeasurement of positional information of the movable body is switchedfrom one of the first and second measurement units to the other, so thatmeasurement results of the first and second measurement units match eachother.
 77. The exposure method according to claim 72 wherein light thatenters the inside of the movable body is irradiated on a predeterminedpoint in an irradiation area of the energy beam.
 78. The exposure methodaccording to claim 72 wherein the predetermined point on which the lightthat enters the inside of the movable body is irradiated is an exposurecenter.
 79. A device manufacturing method, the method comprising:exposing a substrate using an exposure method according to claim 72; anddeveloping a substrate which has been exposed.